Highly filled, dense, thermoplastic based compositions which have ceramic-like properties are desirable because they may be used in applications usually reserved for ceramics or filled thermosets. This is because of the relative ease with which thermoplastics may be fabricated. In the above-mentioned copending applications, one of the applicants in this commonly assigned application has reported that certain polymers may be combined with exceptionally high levels of inorganic fillers to result in molding compositions which are capable of being molded into articles having ceramic-like properties. These polymers are selected from the group consisting of polycarbonates, polyetherimides and copolymers thereof, polycylclohexyldimethylene terephthalates and copolymers thereof, polypropylene and polybutylene terephthalates and copolymers thereof, polyethylene terephthalates and copolymers thereof, polyimides, polyester carbonates, polyphenylene sulfides, polyamides, polyamideimides, polyarylates, polymethylpentenes, polysulfones, polyether sulfones, polystyrenes, rubber modified high impact polystyrenes, acetals, SAN, SMA, ASA, modified polyphenylene ethers, polyether ketones, ABS, PVC, PFA, ECTFE, ETFE, PVDF, liquid crystal polymers and combinations thereof. Such thermoplastics, and mixtures of any of them are combined with 30%-80% by weight of a filler selected from zinc oxide or barium sulfate, zirconium oxide, zirconium silicate or mixtures of any of them. In one of the copending applications, it is disclosed that useful such compositions are also provided with an even broader range of filler content, e.g., 20%-90%, if careful attention is paid to the flexural strength of the resulting molded articles--the maximum permissible flexural strength being 7500 psi when measured in standard ASTM Test Methods. Both copending applications specifically exemplify compositions comprising copolyetherimide ester resins, poly(1,4-butylene terephthalate) and zinc oxide, as well as such compositions including also polycarbonate resin.
It has now been discovered that many new polymer blends comprising copolyetherester resins, copolyetherimide ester resins, or mixtures thereof and linear and/or branched polyesters having high loadings of the mineral fillers over a broad resin composition range will surprisingly provide highly dense, readily processible compositions having high impact strength. Addition of the copolymers in combination with the such polyesters is also found to provide desirably lower Shore hardness, improved dynamic fatigue properties, paintability, extrudability and injection moldability. The new compositions can also contain reinforcing fillers and/or flame retardant agents.
The new compositions may be used to mold useful objects such as tableware, dishes, bowls, mugs, plumbing fixtures and the like which require a smooth surface. In addition, the selection of the proper level of filler will provide a density in the molded article which approaches the density of ceramics, e.g., 2.0 to 2.5 g/cc.
Accordingly, it is an object of this invention to provide novel molding compositions which contain a high level of fillers which will provide a smooth surface.
It is also an object of this invention to provide novel molding compositions which have a high level of fillers which will have a ceramic-like feel and density.
It is also an object of this invention to provide novel molding compositions having special utility for making molded articles.
It is also an object of this invention to provide novel molding compositions which may be employed for making highly dense molded articles.
These and other objects of the invention will become apparent from the present specification.